Positioning effect of type-II GaSb/GaAs quantum ring layer on solar cell performances

In this work, we demonstrate the positioning effect of the type-II quantum ring (QR) on the solar cell efficiencies. The QR layer was placed in either p-type or n-type region to test its effect on the performance. Under one Sun condition, the one with p-type QR layer has better efficiency and open-circuit voltage. But this advantage loses quickly when the sunlight is concentrated over 20 times. From the concentrated sunlight measurement, the sample with QR layer in the n-type region can sustain the V_oc reduction until 80 Suns.